Appendix C
Data structure of the FDC model
parameters
This appendix explains the data-format that was used to implement the parameters
of the Beaver dynamics model inMATLAB/SIMULINK. The numerical values of these
parameters has been presented in appendix B; a detailed description of the SIMULINK
model itself can be found in chapter 8.
C.1 Defining the model parameters in the MATLAB workspace
The aircraft model from the FDC toolbox reads its model data from the MATLAB
workspace. The exact structure of this data is highly dependent of the aircraft under
consideration; for the Beaver, most parameters have been stored in three parameter
matrices and one parameter vector. The parameters must be present in the MATLAB
workspace before running a simulation of the airplane model, or applying an
analytical SIMULINK or FDC function to this model.
This data-structure may not be suited for the implementation of different aircraft
models within the FDC structure. Although any suitable data-structure can be used,
it is recommended not to change the definitions of the vector GM1 and matrix GM2,
which contain mass-distribution data and information about the airplane’s geometry,
except for enhancing the model for non-constant mass and/or mass-distribution.
This is due to the fact that these two matrices are used by aircraft-independent subsystems
as well, contrary to the aerodynamic and propulsion parameter matrices AM
and EM, which are used by aircraft-dependent blocks only.
The parameters can be loaded from the file AIRCRAFT.DAT, which can normally
be found in the DATA subdirectory, using the utility DATLOAD (see section 12.4.2). If
this datafile has somehow inadvertently been deleted, it can be re-created by running
the program MODBUILD (see section 12.6.1). The definitions of the parameter vector
and matrices for the Beaver model will be given below; the numerical values of the
parameters have been listed in appendix B, along with some general information
about the Beaver aircraft.
To change the values of the parameters, e.g. in order to implement a model of a
different aircraft, the easier method is to create a customized copy of MODBUILD.M.
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